Corsair Flash Padlock
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Storage Capacity: 2 Gbytes, 4 Gbytes
Casing: PIN pad built into form factor
Encryption: None
Special features: Requires PIN to mount drive
Speed: Not listed
Price: $30 / $50

Whether encryption takes place through hardware or software, password authentication requires custom code for a particular operating system. This is why almost all of the above solutions provide Windows-only protection.

Corsair Flash Padlock takes another approach. Before it will work at all, you have to authenticate yourself to a separate security processor on the device using a six-button keypad. If you enter the correct PIN, the device will function as a normal, unencrypted USB drive. Because you don't need to borrow the resources of the host computer for authentication or encryption, you can be assured of the ability to plug the Corsair Flash Padlock into any computer, whether Mac, PC, or Linux, at home, at the office, or on the road. After you unplug the drive from the USB port, it re-locks in 15 seconds.

The benefit of device-based authentication is that nobody can steal your device password using keystroke logging software. Plus, because the device presumably turns into a thumb-shaped brick until the PIN has been entered, the question of encryption becomes moot. However, it might still be worthwhile to encrypt individual files or folders on the drive, because you never know.

You can set a PIN up to 10 digits long, and an online registration tool will store your PIN as a backup. The PIN pad and separate security processor are powered by a 3-volt lithium battery.

Vendor, Device, Storage Capacity, Casing, Speed: You decide
Encryption: Software-based
Special features: Works on any drive

If you tote around a briefcase handcuffed to your wrist, people will think you're carrying large quantities of cash. The same principle applies to people who carry USB drives with fingerprint readers or keypads with "Secure" etched on the casing. It's not exactly subtle, and so if you want to keep secret the very fact that you have sensitive files, the best approach may be to use an ordinary, unencrypted USB drive.

TrueCrypt for Windows, Mac, and Linux allows you to create an encrypted, password-protected "container" for your sensitive documents. The software requires sufficient access on a host computer, which precludes usage at some computer labs and Internet cafés.

TrueCrypt prompts the user to select a strong password with at least 20 mixed-case/mixed-symbol characters, allowing up to 64 characters. Numerous other configuration options cater to your precise level of paranoia. However, these same extensive options mean that TrueCrypt is not the answer for an enterprise roll-out to non-technical users.